Control for gaseous electric discharge lamps



Filed April 24, 1940 CONTROL FOR GASEOUS ELECTRIC DISCHARGE LAMPS Nov. M), 1942.

INVENTOR fry/)MA )'ost.

ATTORN Patented Nov. l0, 19.42

DISCHARGE Irvine and, momma, ohio, assignmfo westinghouse Electric Manufacturing Company,'

East Pittsburgh, Vania lla., a corporation of Pennsyl- Application April 24, 1940, Serial No. 331,377

6 Claims. (Cl. 176-124) My invention relates, generally, to lighting control systems and, more particularly. to systems and apparatus for controlling the operation of gaseous electric discharge lamps of the type which are started on one voltage and operated on a different, usually lower, voltage. One example of a lamp of this type is the fluorescent mercury vapor lamp and it is for the control of a lamp of this character that my invention is particularly adapted.

Hereto'fore, iti has been the usual practice to of an ornamental nature, it is necessary to install them in a non-exposed manner in a more or less inaccessible place, usually in the wiring trough provided in the building or other structure in which the lamp is to be used. Furthermore, as these control umts are made up in a permanent form by placing the various control elements in the casing andsealing it with insulating material, it is very dimcult to replace or repair any element thereof without tearing the unit down and rebuilding it in the original form.

It has been found that of all the'elements of the control unit, the thermal switch is the one most likely to fail and require replacement. This is due to the severe duty imposed on it in starting the lampY frequently in normal usage and under conditionsof lamp failure where the cathodes remain intact but the lamp does not start because of lack of emission material on'the cathodes.

Therefore, it is apparent that the control units heretofore usedare not entirely satisfactory from tire control unit which is not only time consming for the reason that the wiring trough must be opened and the circuits disconnected. but is also Vexpensive and keeps the .lamp out of service for longer periods of time than is usually del sirable.

Accordingly, it is the oblect of my invention to provide an improved control for gaseous electric discharge lamps, which shall be of simple construction, economical to make and use, and

the element thereof which is most likely to fail in normal service.

A more speciiic object of the invention is to provide for controlling the operation of a gaseous electric discharge lamp by means of a therf mal control switch located in or`oh the socket or holder for the lamp.

Another object of my invention is to Provide a control system for a gaseous electric discharge lamp whichutilizes a thermal control switch located adjacent the lamp and in an accessible position separate and apart from otheroontrol elements of the control system.

A further. object of my invention is to provide a lamp socket or holder for gaseous electric discharge lamps which supports or contains theV thermal control switch for the lamp.

These and other objects of my invention will become more apparent from the following detailed description when considered in conjunction with the drawing, wherein:

Figure 1 is a diagrammatic view of a starting and operating circuit for a gaseous electric discharge lamp embodying the principal features of my invention; I

' Fig. 2 is a view in elevation showing one way in which a thermal control switch of one type may be mounted on one of th'e lamp sockets or holdeI'S;

Fig. 3 is a View similar to that of Fig. 2 showing a control relay of another type mounted on the socket and also showing diagrammatically the control and operating circuit for the lamp;

fFig. 4 is a fragmentary view in elevation of a lamp and socket showing a still different way of mounting the control switch of Fig. 3 on the socket; and

Fig. 5 is a view similarY to Fig. 3 showing the` mounting for a -still differentV type of control relay or switch.

Referring to Figure 1 of the drawing, the numeral I0 designates generally a gaseous electric discharge lamp of the fluorescent mercury vapor type which is to be operated from a suitable source of voltage connected to the conductors il and I2. 1

'I'he lamp i8 is of well known construction and may comprise a tubular glass enveiope sealed at both ends and provided with pair; of terminal prongs or pins il to which the cath-v odes I5 are connected on the inside of the envelope. The particular lamp illustrated is known Y as a iiuorescent lamp and like other mercury vapor lamps, it isof the dual voltage type mean'- in which provisions made for readily replacing 55 ins that it is started at a dennite voltage 'ma 2' operatedat a diierent voltage. This requires the use of a reactor or atransformer having a high internal reactan'ce and, in this instance, a

reactor i6 is shown connected in the lamp circuit.

In order to provide for supporting the opposite' tiveness of the reactor IB to control the voltageA impressed across the lamp terminals during the starting and operating periods, there is provided a control switch 2i which may -be of any suitable type, such, for example, as the thermal switch illustrated. It is to be understood that the pary ticular type of control switch used is not of any particular importance insofar as the present invention is concerned so long as it will function to provide the desired control of the lamp during the starting and operating periods.

The control switch 2i may comprise, generally, a normally-closed contact element 22 and an associated heater element its and constructed so that the contact element 22 is opened in response to they heat to which it is subjected by the associated heater element The contact element 22 of the control switch being normally closed, the reactor i6, cathodes l I5 of the lamp and heater element 23 of the control switch are connected in series circuit relation to the supply conductors it and t2. When these conductors are energized or connected to a suitable source, the heater element at! causes the'contact element 2a to open this series circuit after the cathodes have been heated thus producing a high peak voltage or kick from the reactor i6 which starts' the lamp -by initiating a discharge between the heated cathodes i5.

Heretofore, it has been the practice to mount the control switch 2t, reactor l@ and condenser 2li, the latter being connected across the lamp terminals to eliminate radio interference, in a common casing or box and ll the same with a suitable insulating compound to form a permanent unitary assembly which may be referred to as a control unit.

As pointed out hereinbefore, this practice is uneconomical and unsatisfactory from the stand point of satisfactory operation and maintenance as the control switch is subjected to a rellatively heavy duty cycle in the frequent starting'of the lamp under ordinary operation when the llamp is -new and' in good operating condition. The control switch is subjected to a heavier duty cycle in some instances when the lamp begins to approach the end of its normal life and the cathodes begin to deteriorate which makes it more difilcult to start lthe lamp often requiring several attempts, and consequently, several operations oi the control switch. .Should the lamp fall tostart the control switch may function repeatedly in attempting to start it if the lamp is not replaced or disconnected from the source.

Therefore, in order to provide for readily and `economically replacing control switches which thave failed, my invention provides for mounting the control'switch, regardless of its particular type or construction and whatever other control element may be incorporated therein, adjacent the lamp in a more or less exposed and accessiblel position.' y

Preferably the control switch may be mounted on one of the lamp sockets or holders as shown diagrammatically in Fig. 1. In this instance,

Athe control unit 25 is made up only of a suitable casing (not shown) for housing the reactor I6 and condenser 24 and which is suitably filled with an insulating compound in the usual manner. Since the condenser 24 is small as comparedto the reactor i6 it may be built into or combined with the control switch in some instances and it is to be understood that my invention contemplates such an arrangement,

Fig. 2 shows the way in which the control switch 2i may be mounted directly on the socket Il, the sockets il and la being mounted on top of the cover 29 of the wiring trough or any other suitable support, the circuit connections being the same as shown in Fig. l.

Fig. 3 shows the physical mounting of a different type of control switch 26 on the socket il. In this instance, the control switch 2S, or glow relayc tube as it is sometimes calledcomprises.

generally a glass envelope 2l provided with a -screw contact base 28 similar to a small lamp bulb which is screwed into a suitable' threaded opening provided in the base portion of the socket as shown. 1

The envelope 27 contains the control or switch elements together with an ionizable medium which function, when heated by the flow of current therethrough, to rst close the circuit through the cathodes of the lamp in series and then break the circuit to produce the lnecessary "peak voltage from the reactor to start the lamp.

In this embodiment of the invention, the sockets il. and I8 are surface mounted as 1n Fig. 2 andthe circuit connections are as shown. `The control switch functions in the same general way to control the lamp as in Fig. l.

In Fig. 4 there is shown a diierent type o mounting for the control switch of Figi 3 wherein the main socket is ush mounted and an auxiliary attachment or adapter 3l is provided for mounting the control switch 25 on the main socket il. and adapter 3l are secured to the cover 2Q by means of a single bolt 32, the cover being provided with a suitable opening beneath the lamp through which the control switch 26 extends in a more concealed position but still in an accessible position. In .this instance, the control switch' may be readily removed for inspection or replacement by removing the lamp from the socket or sockets.

Fig. 5 shows the physical mounting of a still diderent type of control switch 33, which is a different form of the glow relay tube, and which is made in the form of a metal envelope containvin the adapter 3l to hold the control switch in .position .and complete the electrical circuit through its control elements. Control switch 33 is also mounted beneath the lamp and extends through an opening in the support 29.

In View of the foregoing, it will 4be apparent that I have provided for mounting the control In this 'instance the main socket ii switch regardless of its type or construction, in a readily accessible position on or adjacent to the socket or lamp-holder so that it is entirely lndependent of any of the other control elements used to start and control the operation of a lamp of the character described. By so doing, I have made it possible to use and operate these lamps and, particularly, the fluorescent lamp, `more economically and to greater advantage than hereto- 1 derstood that other embodiments thereof may be made without departing from the spirit and scope thereof as defined by the appended claims.

I claim as my invention:

1. The combination with a gaseous electric discharge lamp and a, source of voltage therefor, of a socket for the lamp, a control unit comprising a reactor, and a thermal control switch for controlling the electrical connections between the lamp, control unit and a source of voltage to produce a peak voltage for the discharge of the lamp, said thermal control switch being rigidly supported by the lamp socket in a mechanically detachable manner apart from the control unit in an accessible position, whereby it may be readily removed !or inspection or replacement.

2. In combination, a gaseous electric discharge lamp, a plurality of sockets for supporting and conducting current to the lamp, a reactor, a glow relay device for controlling the lamp, said glow relay device functioning to start the lamp discharge by rst connecting the reactor and electrodes of the lamp in series circuit relation to a;

source of voltage for a predetermined time and then opening said circuit to produce a peak voltage, and means for detachably mounting said V glow relay device as a separate element on one of said sockets adjacent one end of the lamp lin an ducting current to the lamp,'said sockets being i adapted for mounting upon -a support, a reactor,

circuit connections for the lamp and' reactor to the voltage source through the lamp sockets, and a time-delay control switch interposed in'said connections between the reactor and the lamp for controlling the starting operation of the lamp by rst closing and then openo -ation of the lamp by rst connecting the reactor in series with the cathodes of the lamp to a voltage source and then opening said circuit to pro'- duce a peak voltage, and means for detachably securing said thermal control switch to the socket in an exposed position adjacent the lamp where it is readily accessible for inspection and replace-g ment without disturbing thesocket mounting or circuit'connections to the reactor.

5. In` combination, a mercury vapor lamp, a socket for supporting one end of the lamp and conducting current thereto, athermai switch for controlling said lamp, said thermal switch having mounting means thereon, and means on said socket disposed to receive the mounting means of the said switch whereby the switch may be de`- tachably mounted on the socket as aseparate element in close proximityto the lamp and in an exposed and accessible position to facilitate lnspection and removal for replacement purposes. 6. In combination, a mercury vapor lamp, a

socket for supporting one end of the lamp and.

conducting "current thereto, said socket being adapted for attachment to a supporting medium, a thermal switch for controlling said lamp, said thermal switch having a plurality of contact pins thereon for mounting the switch andalso serving as contact elements, and Va socket mounted -on the lamp socket for receiving the contact pins of the switch to support said switch with at least a portion thereof on the same side of the supporting medium as the lamp is located, whereby the said switch may be detachably mounted on the socket in an accessible and readily removable pomtion.

IRVINE A. YOST. 

